The present invention relates generally to a device or apparatus for determining the alignment or orientation of electrical wiring at connectors used for coupling electrical circuits, and more particularly to such a device for checking the orientation of the wiring used for electrical systems such as lighting circuits at terminals of connectors utilized for coupling electrical systems of trailers to corresponding electrical systems in trailer towing vehicles.
In transportation and recreational fields, it is common place to utilize trailers towed by various forms of vehicles, such as tractors, recreational vehicles, small trucks, and automobiles. A large variety of trailers are utilized in these fields ranging from relatively large units such as those used in tractor trailer combinations, down through mobile homes to relatively small units such as utility or boat trailers. Highway safety regulations require that the trailer be at least equipped with lighting systems for night travel and with most trailers being required to include lights as used for indicating vehicle turning and stopping.
The various lights in the lighting systems used on trailers are intended to function concurrently with the corresponding lights on the trailer towing vehicle. To accomplish this goal, a suitable electrical connector is usually positioned between the trailer and the trailer towing vehicle for coupling the wiring of the lighting circuits in the trailer towing vehicle to the wiring for corresponding lighting circuits in the trailer. The electrical connectors utilized for such purposes are usually of the disconnectable plug-receptacle type wherein a plurality of wires leading from particular lights in the trailer towing vehicle are usually coupled to individual pin terminals in the plug portion of the connector while wires leading to corresponding lights in the trailer are coupled to individual socket terminals in the receptacle portion of the connector. In order to assure that the proper lighting sequence occurs, each wire leading from a particular light in the trailer towing vehicle that is connected to a pin in the connector must match with a wire leading to a corresponding light in the trailer and connected to a socket engaging the particular pin. Normally, the connectors used between trailers and trailer towing vehicles are provided with a standardized, factory recommended, wire connecting pattern at each pin and socket in the connector to achieve standarization in connector applications and thereby minimize wire orientation problems in trailer lighting applications.
However, it has been found that the lighting systems in many trailers as well as those in trailer towing vehicles are often miswired at the connectors even though the wiring for the lighting systems is most frequently color-coded according to accepted standards and the terminals at the connector are appropriately marked and/or located in certain standardized positions on the connector body. Such miswiring presents considerable difficulties in providing the proper lighting activation on the trailer as well as presenting problems associated with any correcting of the wiring at the connector. These wiring problems at the electrical connector frequently occur in a trailer leasing and rental applications and in the heavy truck industry where tractors are often mated with different trailers. In many instances, the connector portion attached to the trailer towing vehicle is different from that of the trailer so as to necessitate the changing of at least one of the connector portions to provide connector conformance. Such installation of new connectors or connector portions on trailer towing vehicles and/or trailers also presents problems in achieving the correct wiring orientation at the connector. In addition to trailer lighting, the connectors are often used to couple the DC charging circuit of the trailer towing vehicle to storage batteries used in the trailers or for the coupling of hot electrical leads from the trailer towing vehicle to an electrical mechanism carried by the trailer.
Previous efforts in determining the correct wiring at the connector and the correcting of the wiring at such connectors have been somewhat inefficient and cumbersome. Normally, a hit or miss type approach is used wherein the trailer towing vehicle is attached to the trailer and a particular light system on the towing vehicle is activated so that the wiring to the matching lighting system on the trailer can be checked. If the wiring is correct at one point through the connector then another lighting system on the towing vehicle is activated to check the corresponding lighting system on the trailer. When an incorrect lighting sequence occurs, the wires at the connector are moved from terminal to terminal, usually on the trailer portion of the connector, until the correct wiring position for the desired light operation is achieved. This process is repeated until all the wiring circuits for the light systems on the trailer are correctly aligned at the connector. The correctness of the wiring orientation for the charging circuit hookup is also more difficult to ascertain since it requires the operation of the engine on the trailer towing vehicle to energize the charging circuit. This haphazard moving of the wires from terminal to terminal to provide the desired lighting and charging circuit operation often leads to the miswiring of the connector when the trailer is to be coupled to a different trailer towing vehicle.